Designing the connection of the end of the sealing cuff which is the outer end relative to the housing of the ball joint with the ball pivot is problematic, because both radial and axial sealing between the ball pivot and the housing must be achieved despite the deflecting movement and the rotary movement of the ball pivot relative to the housing.
In prior-art designs, the sealing cuff has at this end an edge profile in the form of a bead-like thickened area with an inner bearing surface, which is in direct contact with the generated surface of the ball pivot or with a retaining ring firmly attached to the ball pivot. The sealing cuff may be held on the surface of the ball pivot by the intrinsic tension of the material or by the tension of a spring ring mounted externally. Circular tongue-and-groove designs have been known to ensure the axial position. Imperfect sealing of the radial sealing seat and also of the axial sealing seat very easily lead to corrosion on the vehicle part containing the bearing lug for fastening the ball pivot and on the ball pivot itself. Thus, the service life of a ball joint depends essentially on the extent to which it is possible to avoid corrosion in this area.
It is known from West German Patent No. DE-PS 37,05,847 that the edge profile of the sealing cuff on the ball pivot can be inserted into a retaining ring arranged on and adhering to the ball pivot. The retaining ring is provided with a coating of an elastic material on the mounting surface and on the support surface with which it is supported on a vehicle part.
It is known from British Patent No. GB-PS 1,477,649 that one end of the sealing cuff made of an elastically deformable material can be fastened in an annular groove provided on the circumference of the housing, and a profile of the other end, which is positive-locking in this axial direction, can be inserted into a circumferential recess of a support ring arranged on and adhering to the ball pivot. This support ring has a bearing surface sealingly surrounding the ball pivot, as well as a support surface that is radial thereto, which is supported by the vehicle part containing the bearing lug for fastening the ball pivot. The sealing cuff with its seating surface is thus able to be temporarily lifted off from the support ring in order to enable air and excess grease to escape from the inner space of the sealing cuff. However, this measure is not directed toward corrosion protection.
Finally, it was proposed in Swiss Patent No. CH-PS 465,971 that the support ring, as is known from West German Patent No. DE-PS 37,05,847, be made of a hard plastic which is rotatably surrounded by the bead of the sealing cuff, so that the sliding surface between the bead of the sealing cuff and the support ring is arranged in a protected depressed area.